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Driver Current Loop Checks Before FAT — STEPMOTECH engineering article

Driver Current Loop Checks Before FAT

Driver settings are often treated as late-stage commissioning details, but most field surprises were already visible during FAT with the right logging.

FAT is the cheapest place to catch tuning drift

By the time the cabinet is on site, a current-loop mismatch becomes a schedule problem. FAT gives enough signal to fix it while the hardware team is still close to the project.

We keep one short log template for idle current, thermal state, and protection events so factory and field teams read the same evidence.

  • Verify idle current after the final enclosure build, not before.
  • Confirm protection thresholds with the intended PSU, not a bench supply.
  • Save one reference log from the customer acceptance build.

FAT logging set

These checks are quick enough to repeat on every cabinet build.

SignalTargetNotes
Idle currentExpected hold stateAvoid unnecessary heating at dwell.
Current rippleWithin driver specNo resonance burst in low-speed window.
Protection events0 unintended tripsDocument every threshold that was changed.

Commissioning log structure

station: FAT-02
psu: 48V-10A
idle_current_pct: 55
trip_events: []
ripple_ok: true
MH

Marco Hein

Drive Systems Architect — STEPMOTECH

Marco focuses on driver tuning, industrial Ethernet integration, and test workflows for distributed motion systems.

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